JP7205280B2 - Thermosetting resin composition, bulk molding compound, and molded article - Google Patents

Description

The present invention relates to thermosetting resin compositions, bulk molding compounds, and molded articles.

A thermosetting resin composition obtained by adding a low shrinkage agent, an inhibitor, a curing agent, a filler, a release agent, a reinforcing agent, etc. to a thermosetting resin such as an unsaturated polyester resin or a vinyl ester resin, and kneading the mixture with a kneader. The material has advantages such as electrical insulation, heat resistance, flame resistance, high rigidity, and dimensional stability. Among the thermosetting resin compositions, a bulk molding compound (hereinafter abbreviated as "BMC") is formed into a molded product by a molding method such as compression molding, transfer molding, or injection molding. can be

In recent years, electronic components have become more powerful (higher density) and smaller (lighter), and a large amount of heat tends to accumulate inside electronic components, which reduces the operating efficiency of electronic components. There is a problem to To solve this problem, a thermosetting resin composition (BMC) with excellent thermal conductivity is desired.

As a method for imparting thermal conductivity to a thermosetting resin composition, inorganic fillers such as boron nitride, aluminum nitride, aluminum oxide (alumina), magnesium oxide, and magnesium carbonate having high thermal conductivity are added to the thermosetting resin composition. is known. Among these inorganic fillers, boron nitride is a filler having high thermal conductivity, but is less practical in terms of cost and has a hexagonal flaky crystal structure. There is a problem that it is oriented and anisotropy occurs in the thermal conductivity of the molded product. Also, aluminum nitride has no anisotropy in thermal conductivity, but has the problem of low practicality in terms of cost, as with boron nitride, and is easily hydrolyzed to generate ammonia. Furthermore, aluminum oxide has a high Mohs' hardness, which causes the problem of abrasion of the mold during the molding process.

Therefore, a thermosetting resin composition using magnesium oxide, which is an inorganic filler having relatively high thermal conductivity, no anisotropy, and low cost, has been proposed (for example, Patent Document 1 3). However, these thermosetting resin compositions have a problem that the amount of magnesium oxide to be filled is small, and the thermal conductivity of the cured product (molded article, molded article) is low.

Further, in order to obtain a high thermal conductivity cured product, a thermosetting resin composition using a high filling of a high thermal conductivity filler such as magnesium oxide has also been proposed (see, for example, Patent Documents 4 and 5). .
However, since these thermosetting resin compositions have a very high volume content of solids such as high thermal conductivity fillers and fiber materials, the kneadability of the resin composition and the fluidity of the obtained resin composition was insufficient.

Therefore, there has been a demand for a thermosetting resin composition which has excellent kneadability and fluidity, and which can give molded articles having excellent thermal conductivity and flame retardancy.

JP 2003-192885 A JP 2008-150486 A JP 2009-102586 A Japanese Patent No. 5636169 Japanese Patent No. 6419090

The problem to be solved by the present invention is to obtain a molded article that has excellent kneadability, high storage stability that does not easily cause viscosity increase over time, and excellent thermal conductivity and flame retardancy. It is to provide a thermosetting resin composition and a molded article using the same.

The inventors of the present invention have made intensive studies to solve the above problems, and found that a thermosetting resin composition containing epoxy (meth)acrylate, a polymerizable monomer, a specific inorganic filler, and an organic peroxide is , which has excellent kneadability, has high storage stability that does not easily cause viscosity increase over time, and can provide molded articles having excellent thermal conductivity and flame retardancy, and completed the present invention. let me

That is, the present invention is a thermosetting resin composition containing an epoxy (meth)acrylate (A), a polymerizable monomer (B), an inorganic filler (C), and an organic peroxide (D), , a thermosetting resin composition characterized in that the inorganic filler (C) contains calcium carbonate (c1), aluminum hydroxide (c2) and magnesium oxide (c3), BMC and a molded article using the same It provides.

The thermosetting resin composition of the present invention has excellent kneadability and storage stability, and the molded article using the thermosetting resin composition has excellent thermal conductivity and flame retardancy. It is very useful as a support for electronic parts used in home appliances, automobiles, etc., a motor sealing material for electric automobiles, a holder for lithium ion secondary batteries, a case for lithium ion secondary battery assemblies, and the like.

The thermosetting resin composition of the present invention is a thermosetting resin containing an epoxy (meth)acrylate (A), a polymerizable monomer (B), an inorganic filler (C), and an organic peroxide (D). In the composition, the inorganic filler (C) contains calcium carbonate (c1), aluminum hydroxide (c2) and magnesium oxide (c3).

The epoxy (meth)acrylate (A) is obtained, for example, by reacting an epoxy resin with (meth)acrylic acid.

In the present invention, "(meth)acrylic acid" refers to both or one of acrylic acid and methacrylic acid, "(meth)acrylate" refers to both or one of acrylate and methacrylate, and "(meth) ) acryloyl” refers to both or one of acryloyl and methacryloyl;

Examples of the epoxy resin include bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol fluorene-type epoxy resins, bisphenol-type epoxy resins such as bis-cresol fluorene-type epoxy resins, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, and the like. Phenol glycidyl ether, dipropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ether of alkylene oxide adduct of bisphenol A, such as novolac type epoxy resin, oxodoridone modified epoxy resin, brominated epoxy resin of these resins , glycidyl ethers of polyhydric alcohols such as diglycidyl ether of hydrogenated bisphenol A, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, 1-epoxyethyl-3,4 - Alicyclic epoxy resins such as epoxycyclohexane, diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl-p-oxybenzoic acid, glycidyl esters such as dimer acid glycidyl ester, tetraglycidyldiaminodiphenylmethane, tetraglycidyl-m -glycidylamines such as xylenediamine, triglycidyl-p-aminophenol, N,N-diglycidylaniline, 1,3-diglycidyl-5,5-dimethylhydantoin, heterocyclic epoxy resins such as triglycidyl isocyanurate, etc. mentioned. Among these, bifunctional aromatic epoxy resins are preferred because they are superior in molded product strength, handling properties of molding materials, and fluidity of molding materials during molding, and bisphenol A type epoxy resins and bisphenol F type epoxy resins are more preferable. preferable. These epoxy resins can be used alone or in combination of two or more.

The reaction between the epoxy resin and (meth)acrylic acid is preferably carried out at 60 to 140° C. using an esterification catalyst. A polymerization inhibitor or the like can also be used.

Examples of the polymerizable monomer (B) include styrene, α-methylstyrene, chlorostyrene, dichlorostyrene, divinylbenzene, t-butylstyrene, vinyltoluene, vinyl acetate, diarylphthalate, and triarylcyanate. Monomers having a nurate, (meth)acryloyl group, and the like can be mentioned. These polymerizable monomers can be used alone or in combination of two or more.

Examples of the (meth)acryloyl group-containing monomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, (meth) ) t-butyl acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, stearyl (meth)acrylate, tridecyl (meth)acrylate , 2-hydroxyethyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, ethylene glycol monomethyl ether (meth)acrylate, ethylene glycol monoethyl ether (meth)acrylate, ethylene glycol monobutyl ether (meth)acrylate, ethylene glycol monohexyl ether (meth) acrylate, ethylene glycol mono-2-ethylhexyl ether (meth) acrylate, diethylene glycol monomethyl ether (meth) acrylate, diethylene glycol monoethyl ether (meth) acrylate, diethylene glycol monobutyl ether (meth) acrylate, diethylene glycol monohexyl ether ( meth) acrylate, diethylene glycol mono-2-ethylhexyl ether (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxypropyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) ) acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di( meth)acrylate, neopentyl glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, Neopentyl glycol di(meth)acrylate, 1,3-bis[(meth)acryloyloxy]-2-propanol, 2,2-bis[4-(meth)acryloxyethoxyphenyl]propane, 2,2-bis[ 4-(meth)acryloy diethoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxy-polyethoxyphenyl]propane, tetraethylene glycol di(meth)acrylate, ethylene oxide-modified di(meth)acrylate of bisphenol A, isocyanurate Examples thereof include ethylene oxide-modified di(meth)acrylate of acid, pentaerythritol di(meth)acrylate monostearate, and the like.

In addition, when it is necessary to further improve the performance of the surface of the cured product, such as abrasion resistance, scratch resistance, and chemical resistance, a monomer having two or more (meth)acryloyl groups is added to the monomer ( B) is preferably used, and more preferably a monomer having 3 or more (meth)acryloyl groups is used as the monomer (B). Monomers having 3 or more (meth)acryloyl groups include, for example, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethylene of trimethylolpropane Oxide-modified tri(meth)acrylate, propylene oxide-modified tri(meth)acrylate of trimethylolpropane, ethylene oxide-modified tri(meth)acrylate of isocyanuric acid, ethylene oxide/ε-caprolactone-modified tri(meth)acrylate of isocyanuric acid, di Pentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate and the like.

In the thermosetting resin composition of the present invention, the mass ratio [(A)/(B)] between the epoxy (meth)acrylate (A) and the polymerizable monomer (B) is 90/10 to 30. A range of /70 is preferred, a range of 80/20 to 40/60 is more preferred, and a range of 70/30 to 50/50 is even more preferred.

Further, in the thermosetting resin composition of the present invention, a resin component other than the epoxy (meth)acrylate (A) and the polymerizable monomer (B) is blended within a range that does not impair the effects of the present invention. You may Examples of such other resin components include resins such as unsaturated polyesters and urethane (meth)acrylates. The resin component in the present invention contains the polymerizable monomer (B).

The inorganic filler (C) has excellent kneadability and storage stability, and provides a molded article having excellent thermal conductivity and flame retardancy, so calcium carbonate (c1), aluminum hydroxide ( c2), and magnesium oxide (c3).

The average particle size of the calcium carbonate (c1) is preferably in the range of 1 to 10 μm, more preferably in the range of 1 to 5 μm, because the kneadability of the thermosetting resin composition of the present invention is further improved.

In addition, in the thermosetting resin composition of the present invention, the amount of the calcium carbonate (c1) blended is such that kneadability, storage stability, thermal conductivity and flame retardancy of the resulting molded article are well balanced. Therefore, it is preferably in the range of 100 to 300 parts by mass, more preferably in the range of 100 to 200 parts by mass, with respect to the total 100 parts by mass of the epoxy (meth)acrylate (A) and the polymerizable monomer (B). .

The average particle size of the aluminum hydroxide (c2) is preferably in the range of 1 to 30 μm, more preferably in the range of 1 to 15 μm, because the kneadability of the thermosetting resin composition of the present invention is further improved.

In addition, in the thermosetting resin composition of the present invention, the amount of the aluminum hydroxide (c2) blended is more excellent in kneadability, thermal conductivity of the obtained molded article, and flame retardancy. It is preferably in the range of 100 to 300 parts by mass, more preferably in the range of 100 to 200 parts by mass, based on the total of 100 parts by mass of the epoxy (meth)acrylate (A) and the polymerizable monomer (B).

The average particle size of the magnesium oxide (c3) is preferably in the range of 40 to 120 μm, more preferably in the range of 60 to 100 μm, since the thermal conductivity of the molded article of the present invention is further improved.

When using the magnesium oxide (c3), the compounding amount of the epoxy (meth)acrylate ( It is preferably in the range of 300 to 750 parts by mass, more preferably in the range of 400 to 650 parts by mass, based on the total of 100 parts by mass of A) and the polymerizable monomer (B).

In addition, the thermosetting resin composition of the present invention may contain other inorganic fillers such as boron nitride, aluminum nitride, aluminum oxide (alumina), magnesium carbonate, etc., within a range that does not impair the effects of the present invention. I don't mind.

In the present invention, the "average particle size" is the value of the volume-based average particle size (D50) obtained using a laser diffraction method.

The organic peroxide (D) serves as a curing agent in the thermosetting resin composition of the present invention. Examples of the organic peroxide (D) include diacyl peroxide-based organic peroxides, peroxyester-based organic peroxides, hydroperoxide-based organic peroxides, dialkyl peroxide-based organic peroxides, and ketones. Examples include peroxide-based organic peroxides, peroxyketal-based organic peroxides, alkyl perester-based organic peroxides, and carbonate-based organic peroxides.

The amount of the organic peroxide (D) is 0.5 to 5 parts by mass with respect to a total of 100 parts by mass of the epoxy (meth)acrylate (A) and the polymerizable monomer (B). A range is preferred, and a range of 1 to 3 parts by weight is more preferred.

In the thermosetting resin composition of the present invention, in addition to the above components (A) to (D), a polymerization inhibitor, a curing accelerator, a low-shrinkage agent, and a dispersant are contained within a range that does not impair the effects of the present invention. , a release agent, a reinforcing material, a pigment, a flame retardant, a coloring agent, an antifoaming agent, and the like.

Examples of the polymerization inhibitor include toluhydroquinone, hydroquinone, hydroquinone monomethyl ether, 1,4-naphthoquinone, parabenzoquinone, toluhydronone, pt-butylcatechol, and 2,6-t-butyl-4-methylphenol. etc. The blending amount of the polymerization inhibitor in the thermosetting resin composition of the present invention is preferably in the range of 10 to 1,000 ppm in the thermosetting resin composition of the present invention.

The low-shrinkage agent is added to suppress cure shrinkage of the thermosetting resin composition of the present invention. Examples of the low shrinkage agent include polymethyl methacrylate, polystyrene, saturated polyester, styrene-butadiene rubber, and polyvinyl acetate. These low shrinkage agents can be used alone or in combination of two or more.

The release agent is for facilitating removal of the molded article obtained from the mold after molding the thermosetting resin composition of the present invention using the mold. Examples of the release agent include unsaturated fatty acid amide-based release agents, polyethylene wax-based release agents, metal soap-based release agents, silicone-based release agents, fluorine-based release agents, and the like. Examples of the metal soap release agent include zinc laurate, calcium laurate, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zinc myristate, calcium montanate, zinc montanate, and montanic acid. aluminum, calcium behenate, magnesium behenate, zinc behenate and the like.

Examples of the reinforcing material include fibrous materials such as glass fiber, vinylon fiber, phenol fiber, and polyester fiber. Among these, glass fiber is preferable from the viewpoint of availability. Any of chopped glass, milled glass, roving glass, and the like can be used as the glass fiber.

The thermosetting resin composition of the present invention can be produced by kneading the above components using a kneader such as a planetary mixer or kneader. Also, by adjusting the blending composition so that the obtained resin composition is bulky, a bulk molding compound (BMC) can be obtained.

By using the thermosetting resin composition of the present invention as BMC, a molded article can be easily formed by a molding method such as compression molding, transfer molding, or injection molding.

EXAMPLES The present invention will be described in more detail with reference to examples below.

(Production Example 1: Production of epoxy (meth)acrylate (A-1))
In a 2 L flask equipped with a thermometer, a nitrogen inlet tube, and a stirrer, 671 parts by mass of epoxy resin ("Epiclon 850" manufactured by DIC Corporation, bisphenol A type epoxy resin, epoxy equivalent 188), 310 parts by mass of methacrylic acid, and t 0.28 parts by mass of -butylhydroquinone was charged, and the temperature was raised to 90° C. under a gas flow of a 1:1 mixture of nitrogen and air. 0.60 part by mass of 2-methylimidazole was added thereto, the temperature was raised to 110° C., and the reaction was carried out for 10 hours. After cooling to around 60° C., it was taken out from the reaction vessel to obtain epoxy (meth)acrylate (A-1).

(Example 1: Preparation of thermosetting resin composition (1))
65 parts by mass of epoxy ethacrylate (A-1) obtained in Production Example 1, 30 parts by mass of phenoxyethyl methacrylate, 5 parts by mass of trimethylolpropane trimethacrylate, calcium carbonate (“Softon 1200” manufactured by Bihoku Funka Kogyo Co., Ltd. ; average particle size 1.8 μm) 135 parts by mass, aluminum hydroxide (Showa Denko Co., Ltd. “Hisilite HC-32”; average particle size 8 μm) 135 parts by mass, magnesium oxide (Ube Materials Co., Ltd. “RF- 70C-SC”; average particle size 90 μm) 400 parts by mass, wetting and dispersing agent (“BYK W9010” manufactured by BYK Chemie Japan Co., Ltd.) 8 parts by mass, mold release agent (zinc stearate; manufactured by Sakai Chemical Industry Co., Ltd. “SZ- 2000") and 1 part by mass of an organic peroxide (peroxyester; NOF Corporation "Percure HO (TN)") are kneaded for 12 minutes using a planetary mixer, and then the reinforcing material (Glass fiber / chopped strand; "ECS404-6" manufactured by Chongqing International Composite Materials Co., Ltd.; fiber length 6 mm) 51.5 parts by mass was added and further kneaded for 6 minutes to obtain a thermosetting resin composition (1 ).

(Examples 2-5)
Thermosetting resin compositions (2) to (5) were obtained in the same manner as in Example 1 except that the composition was changed to that shown in Table 1.

(Comparative Examples 1 to 4)
Thermosetting resin compositions (R1) to (R4) were obtained in the same manner as in Example 1 except that the composition was changed to that shown in Table 1.

Using the thermosetting resin compositions (1) to (5) and (R1) to (R4) obtained in Examples 1 to 5 and Comparative Examples 1 to 4, the following evaluations were performed. The thermosetting resin compositions (R2) to (R4) produced in Comparative Examples 2 to 4 were poor in kneadability, and were not evaluated thereafter.

[Evaluation of kneadability]
The appearance of the obtained thermosetting resin composition was visually observed, and kneadability was evaluated according to the following criteria.
⊚: Bulk shape with excellent dispersion of reinforcing material.
◯: It becomes bulky and the reinforcing material is well dispersed.
x: Not bulky.

[Evaluation of storage stability]
The obtained thermosetting resin composition was stored under a temperature condition of 25° C., and the viscosity of the thermosetting resin composition was measured every day. The viscosity was measured using a capillary viscometer (capillary rheometer) under the following measurement conditions. The storage stability was evaluated based on the period (days) during which the increase in viscosity was less than 15% from the initial viscosity, and the longer the period, the better the storage stability.
・Sample amount: 75g
・Measurement temperature conditions: 50°C
・Extrusion speed: 50 mm/min ・Nozzle diameter: 6 mm
・Nozzle length: 10 mm

[Measurement of thermal conductivity]
Compression molding was performed under conditions of a molding temperature of 125° C., a molding pressure of 10 MPa, and a molding holding pressure time of 360 seconds to prepare a flat plate of 300 mm×300 mm×thickness 10 mm, and the thermal conductivity was measured by the QTM method.

[Measurement of oxygen index]
Compression molding is performed under the conditions of a molding temperature of 125 ° C., a molding pressure of 10 MPa, and a molding pressure holding time of 300 seconds to prepare a flat plate of 300 mm × 300 mm × thickness 3 mm, and a test piece for measurement (length: 130 mm) according to JIS K7201. , width: 6.5 mm, thickness: 3 mm) was cut out and the oxygen index was measured.

Tables 1 and 2 show the compositions and evaluation results of the thermosetting resin compositions prepared above.

"Aluminum oxide (alumina)" in the table is "V325F" (average particle diameter 12 µm) manufactured by Nippon Light Metal Co., Ltd.

It was confirmed that the thermosetting resin compositions of Examples 1 to 5 of the present invention were excellent in kneadability and storage stability, and that the obtained molded articles had high thermal conductivity and high oxygen index.

On the other hand, Comparative Example 1, which does not contain aluminum hydroxide, which is an essential component of the present invention, was confirmed to have a low oxygen index.

Comparative Example 2, which does not contain calcium carbonate, which is an essential component of the present invention, was confirmed to have poor kneadability.

Comparative Example 3 is an example containing only magnesium oxide as the inorganic filler, but it was confirmed that the kneadability was poor.

Comparative Example 4 is an example containing magnesium oxide and aluminum oxide as inorganic fillers, but it was confirmed that the kneadability was poor.

Claims (3)

A thermosetting resin composition containing an epoxy (meth)acrylate (A), a polymerizable monomer (B), an inorganic filler (C), and an organic peroxide (D), wherein the inorganic filler (C ) contains calcium carbonate (c1), aluminum hydroxide (c2), and magnesium oxide (c3), and a total of 100 parts by mass of the epoxy (meth)acrylate (A) and the polymerizable monomer (B) , the calcium carbonate (c1) is in the range of 100 to 300 parts by mass, the aluminum hydroxide (c2) is in the range of 100 to 300 parts by mass, and the magnesium oxide (c3) is in the range of 300 to 750 parts by mass. A thermosetting resin composition characterized by being in the range of parts . A bulk molding compound comprising the thermosetting resin composition according to claim 1 . A molded product obtained by molding the bulk molding compound according to claim 2 .